Data acquisition in high-performance clinical 3-D PET has for years been burdened with an unfortunate trade-off. From even the early days of PET, the user has been forced to choose between convenient real-time processing, e.g., on-line rebinning and histogramming, and the collection of the raw information-rich detector-pair list-mode data, e.g., typically in the form of multiple 64-bit packets describing coincident events. Typically, the latter choice also limited the maximum count rate supported without data loss. Systems that could perform both functions at the same time were usually too costly and too complex.
Existing PET data acquisition architecture requires that the on-line processing (LOR-to-bin rebinning and histogramming) be designed with throughput which is no less than the maximum event rate generated by the PET detector array. If the on-line processing throughput fell short, the result was loss of precious PET data during high-count-rate intervals. Achieving extra on-line processing throughput was often expensive if even achievable. In addition, performing on-line processing simultaneous with uncompromising list-mode data acquisitions was difficult if not impossible to achieve.